L is not defined error with Leaflet

javascript html css leaflet

43,140

Solution 1

Switch the order of the two script tags main.js and leaflet.js.

Basically you're instantiating main.js before leaflet.js has been instantiated and therefore L does not exist at runtime for main.js.

 <script src="js/leaflet/leaflet.js"></script>  
 <script src="js/main.js"></script>

Solution 2

I am using mapbox with reactjs and not using leaflet directly, and in my case I was able to resolve the error message: L is not defined no-undef by simply getting it from the window variables:

var L = window.L;

Solution 3

I also have an error with L but in this case the error was that in

 <script  src="./leaflet/dist/leaflet.js"></script>

I was writting: <script type="module" src="./leaflet/dist/leaflet.js"></script>

43,140

Author by

Carson

Updated on July 26, 2022

Comments

Carson almost 2 years

I'm trying to setup leaflet and following the quick start guide on their site. However, I keep getting an error of...

Uncaught ReferenceError: L is not defined
at initmap (main.js:10)
at main.js:6

It seems like an import issue, but I'm stuck. I've tried using the imports provided on their tutorial...

<link rel="stylesheet" href="https://unpkg.com/[email protected]/dist/leaflet.css"
   integrity="sha512-07I2e+7D8p6he1SIM+1twR5TIrhUQn9+I6yjqD53JQjFiMf8EtC93ty0/5vJTZGF8aAocvHYNEDJajGdNx1IsQ=="
   crossorigin=""/>

and

 <script src="https://unpkg.com/[email protected]/dist/leaflet.js"
   integrity="sha512-A7vV8IFfih/D732iSSKi20u/ooOfj/AGehOKq0f4vLT1Zr2Y+RX7C+w8A1gaSasGtRUZpF/NZgzSAu4/Gc41Lg=="
   crossorigin=""></script>

But no luck...

I tried downloading the library and adding it to my project like such...

And then importing from there such like....

'<script src="js/leaflet/leaflet.js"></script>'
'<script src="js/leaflet/leaflet.js"></script>'

But still get the same error.

HTML

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <!--Stylesheets-->
    <link rel="stylesheet" href="css/style.css">
    <link rel="stylesheet" href="css/bootstrap.css">
    <link rel="stylesheet" href="js/leaflet/leaflet.css">
    <!--Scripts-->
    <script src="js/main.js"></script>
    <script src="js/leaflet/leaflet.js"></script>
</head>
<h1>State Capitals</h1>
<!--State Form-->
<div class="form-group">
    <label for="state" class="col-sm-2 control-label">State</label>
    <div class="col-sm-10">
        <select class="form-control" id="state" name="state">
            <option value="">N/A</option>
            <option value="AK">Alaska</option>
            <option value="AL">Alabama</option>
            <option value="AR">Arkansas</option>
            <option value="AZ">Arizona</option>
            <option value="CA">California</option>
            <option value="CO">Colorado</option>
            <option value="CT">Connecticut</option>
            <option value="DC">District of Columbia</option>
            <option value="DE">Delaware</option>
            <option value="FL">Florida</option>
            <option value="GA">Georgia</option>
            <option value="HI">Hawaii</option>
            <option value="IA">Iowa</option>
            <option value="ID">Idaho</option>
            <option value="IL">Illinois</option>
            <option value="IN">Indiana</option>
            <option value="KS">Kansas</option>
            <option value="KY">Kentucky</option>
            <option value="LA">Louisiana</option>
            <option value="MA">Massachusetts</option>
            <option value="MD">Maryland</option>
            <option value="ME">Maine</option>
            <option value="MI">Michigan</option>
            <option value="MN">Minnesota</option>
            <option value="MO">Missouri</option>
            <option value="MS">Mississippi</option>
            <option value="MT">Montana</option>
            <option value="NC">North Carolina</option>
            <option value="ND">North Dakota</option>
            <option value="NE">Nebraska</option>
            <option value="NH">New Hampshire</option>
            <option value="NJ">New Jersey</option>
            <option value="NM">New Mexico</option>
            <option value="NV">Nevada</option>
            <option value="NY">New York</option>
            <option value="OH">Ohio</option>
            <option value="OK">Oklahoma</option>
            <option value="OR">Oregon</option>
            <option value="PA">Pennsylvania</option>
            <option value="PR">Puerto Rico</option>
            <option value="RI">Rhode Island</option>
            <option value="SC">South Carolina</option>
            <option value="SD">South Dakota</option>
            <option value="TN">Tennessee</option>
            <option value="TX">Texas</option>
            <option value="UT">Utah</option>
            <option value="VA">Virginia</option>
            <option value="VT">Vermont</option>
            <option value="WA">Washington</option>
            <option value="WI">Wisconsin</option>
            <option value="WV">West Virginia</option>
            <option value="WY">Wyoming</option>
        </select>
    </div>
</div>
<!--Map-->
<div id="mapid"></div>
<body>

</body>
</html>

JavaScript

var map;
var ajaxRequest;
var plotlist;
var plotlayers=[];

initmap();

function initmap() {
    // set up the map
    map = new L.Map('map');

    // create the tile layer with correct attribution
    var osmUrl='http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png';
    var osmAttrib='Map data © <a href="http://openstreetmap.org">OpenStreetMap</a> contributors';
    var osm = new L.TileLayer(osmUrl, {minZoom: 8, maxZoom: 12, attribution: osmAttrib});

    // start the map in South-East England
    map.setView(new L.LatLng(51.3, 0.7),9);
    map.addLayer(osm);
}

CSS

h1{
    text-align: center;
}

.form-group {
    width: 700px;
    height: 10%;
    border: 1px solid #c3c3c3;
    margin: auto;
    position: absolute;
    left: 0;
    right: 0;
}
#mapid { height: 180px; }